A new way to create a self-righting flood chamber?

[Dashunde]

I have been waffling around trying to decide what boat to buy, and part of that decision revolves around it being self righting.

The Pursuit is a really attractive option, until I consider the self right issue... sure its very doable, but perhaps difficult and I'm not a big fan of the depron sheet method.
All of it is causing me to think about the chamber creation a bit differently.
My idea... (and maybe this is nothing new?)

Before a hole is cut anywhere, lay/clamp/secure the empty hull up on its left edge, fill it with water (or other fluid, I'll get to that in a minute) to the desired level using the hatch opening, motor mount and level in the nose as reference.
That will precisely establish the volume and shape of the chamber wall where it meets the inner hull.
Draw off ~1/8 to 1/4 inch of water (or fluid) to account for the thickness of the chamber wall relative to the hatch/mount/nose.

Then... (and here is the trick)
Slowly pour a yet-to-be-determined product "onto" the water that will float, self-level until it contacts the inner hull all around the edges, AND harden upon the water/fluid... when it hardens and is removed it would be a perfectly shaped and fitted template to use for creating the final chamber wall, and with any material selection luck the template itself may actually become the chamber wall.

So...
Who knows what combination of inexpensive fluids, adhesives, waxes (etc) would behave in this way.. spread out evenly across the top of water/fluid and harden?

Filling the camber area with paraffin wax has also come to mind, it might be hard to pull the whole chunk out, but the flat area should be a really accurate template of the inner hull.
Alternatively, the paraffin could be used as a solid foundation to pour something else onto that would create the first layer of the wall (like epoxy mixed w/ glass fiber?).

[NativePaul]

There are floating waxes that would do it, but good luck getting a good bond on the flood chamber wall after having just waxed the chamber.

All epoxies I know of are heavier than water, but Microballoons are much lighter and alcohol is lighter too, so while I have not done it or heard of it being done, it is plausible to me that you could make an epoxy/microballoon paste thick enough to float then thin it back down enough to be runny and yet it would still float, if I remember my high school chemistry correctly the water should absorb the alcohol rather than the other way round so I think it would cure, but if it absorbs it to quick the epoxy will thicken and not spread over the surface.

You could pour in mercury or gallium which are dense enough to lay up directly on top of, the metal would cost a fortune, but it could be sold on for the same price you pay for it.

The usual process is to make an oversize cardboard template which you refine and retry until it is correct, then cut round it on a sheet of premade glass/carbon/ply and bond that in.

Or just buy a hull that has a chamber prefitted, or doesn't need one, or that comes with one which you need to fit, or that comes with a template to make one easily.

[martin]

If you want a self righting Pursuit take a look at thercbuild.com. Their 32" Arowana self righting hull has the same bottom with a slightly different deck & top to the Pursuit.

[boredom.is.me]

You'd probably be better off filling with something that you can burn out. Think foam and gasoline. Once you have the "form" material in, lay you epoxy/cloth, and let cure. Come back a few days later and pour acetone to eat away the donor material. This would be similar to the lost wax method.

[Dashunde]

Humm.. paraffin should melt around 130-150F.
Maybe pour it in, let it cool, then top it with a few layers of epoxy and fiberglass millings to create the chamber wall.
Then cut the water and air holes, bring the whole thing up to ~150F and simply pour the wax out of the water hole in the rear, leaving behind a sealed empty chamber and epoxy/glass fiber wall.
Clean with correct paraffin-eating solvent, clean any solvent residue, pour thinned epoxy into/along each joint, inside and out to seal and reinforce.

It would take a bit of testing to get the methods figured, but seems doable overall, no?

The hard part is finding a oven large enough, but I suppose a old section of heating ductwork (or simple wood box) and a heat gun would bring it up to pouring temps easy enough without blowing directly on the hull.

[Fast One]

Why don't you just pour a mix of plaster inside, let it harden and then you will have the perfect template.

[boredom.is.me]

How will you remove the plaster?

[Dashunde]

The entire line of thinking here is that once poured into place the chamber wall is never removed, or re-fitted into place.
It also avoids all other three dimensional chamber wall surfaces - it simply forms a flat wall from hull to deck along the entire/desired length.

The plaster idea would probably work if its not poured so long that no wiggle room remains, effectively locking it into place.

[wakenshake]

I think this method could be an awesome way to make accurate templates, most would still have to be two piece to fit through hatch opening, but would of save alot time, i went through least five cardboard templates and four balsa till i was satisfied. unless its a set and forget your still gonna have to prefab wall if running to front cuz its a rpita to get up in there. I had trouble just sanding the tape seams outta inside pursuit, but i have big hands.

one highdea i had was to take a laser and run line up bow with marker then take stiff wire and run down mark then take it out and trace it on paper then do same to topside

other high idea i had when i was filling side of pursuit with water to see how much it needed to selfright then to set the boat in deep freezer level and see it i could get it out in two peices.

then i realized to just push through the templet process even if it took couple extra sheets wood,cardboard,beers,smoke,etc....

I just finished pursuit template for 2plus litres if you wana check out my thread ill post a pic of it up on blueprint bored eventually or could maybe get traceout to scan and email you template. Took me some time but id be willing to help out a brother in need of the same frustrations i was going through.

good luck!

[wakenshake]

just a note I dont recommend to anyone to leave water in there hull to freeze

simply because water expands as freezes. However if you were to keep an eye on it and take it out while the ice is still white in color and all air didnt exscape(before it expands) maybe if you smeared a layer of some warm rubber dip quick over just ice, then teeter around boat on its axis to spread...maybe....then you could pull it out in one peice...if it works...maybe,...

[wakenshake]

i would still maybe like to do the lost foam technique for strength in a one piece composite wall. After a bare hull fg inlay i would then pour foam in fc side, then do another intire inlay right to left up fc wall around to hatch lip, then put at least four more layers on fc walls, who knows where i would end.(i dont race im basher)But man what a pain that would be to layup in the bow even if its precut with templetes you already have,lol.